1. Field of Invention
The invention relates to a process with a seed layer for two steps of electroplating and the corresponding structure, and more particularly to a metal layer deposited at the second step of electroplating capable of being used as a metal pad used to be wirebonded thereto or to have a gold bump or solder bump formed thereover, of being used as a metal bump, or of being used as metal vias connecting neighboring two patterned circuit layers.
2. Description of Related Arts
The continued emphasis in the semiconductor technology is to create improved performance semiconductor devices at competitive prices. This emphasis over the years has resulted in extreme miniaturization of semiconductor devices, made possible by continued advances of semiconductor processes and materials in combination with new and sophisticated device designs. Most of the semiconductor devices are aimed at processing digital data. There are also numerous semiconductor designs that are aimed at incorporating analog functions into devices that are capable of processing digital and analog data, or devices that can be used for processing only analog data. One of the major challenges in the creation of analog processing circuitry is that a number of the components used for analog circuitry are large in size and are therefore not readily integrated into sub-micron devices. Especially, these components may be passive devices, whose size is much huge in comparison with the size of normal semiconductor devices.
Some reference teaches a process with a seed layer for two steps of electroplating, as follows:
Nobuhisa et al. (U.S. Pat. No. 6,707,159) teach a process with a seed layer for two steps of electroplating two gold layers for chip-on-chip package or for chip-on-PCB package.
Chiu-Ming et al. (US2006/0019490) teach a process with a seed layer for two steps of electroplating two gold layers, of electroplating a copper layer and a gold layer, or of electroplating a copper/gold layer and a solder layer.
Mou-Shiung Lin et al. (US2005/0277283) teach a process with a seed layer for two steps of electroplating.